All six great ape species are listed as endangered or critically endangered by the IUCN and experiencing decreasing population trends. One of the threats to these non-human primates is the transmission of pathogens from humans. We conducted a literature review on occurrences of pathogen transmission from humans to great apes to highlight this often underappreciated issue. In total, we found 33 individual occurrences of probable or confirmed pathogen transmission from humans to great apes: 23 involved both pathogen and disease transmission, 7 pathogen transmission only, 2 positive antibody titers to zoonotic pathogens, and 1 pathogen transmission with probable disease. Great ape populations were categorized into captive, semi-free-living, and free-living conditions. The majority of occurrences involved chimpanzees (Pan troglodytes) (n = 23) or mountain gorillas (Gorilla beringei beringei) (n = 8). These findings have implications for conservation efforts and management of endangered great ape populations. Future efforts should focus on monitoring and addressing zoonotic pathogen and disease transmission between humans, great ape species, and other taxa to ensure the health of humans, wild and domestic animals, and the ecosystems we share.

True altruism seen in chimpanzees, giving clues to evolution of human cooperation

Michael Price | Science | 19th June 2017

A pair of studies suggests the evolutionary roots of humanlike cooperation can be seen in chimpanzees, albeit in rudimentary forms (curioustiger/iStockphoto)

Whether it’s giving to charity or helping a stranger with directions, we often assist others even when there’s no benefit to us or our family members. Signs of such true altruism have been spotted in some animals, but have been difficult to pin down in our closest evolutionary relatives. Now, in a pair of studies, researchers show that chimpanzees will give up a treat in order to help out an unrelated chimp, and that chimps in the wild go out on risky patrols in order to protect even nonkin at home. The work may give clues to how such cooperation—the foundation of human civilization—evolved in humans.

“Both studies provide powerful evidence for forms of cooperation in our closest relatives that have been difficult to demonstrate in other animals besides humans,” says Brian Hare, an evolutionary anthropologist at Duke University in Durham, North Carolina, who was not involved with the research.

In the first study, psychologists Martin Schmelz and Sebastian Grüneisen at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, trained six chimps at the Leipzig Zoo to play a sharing game. Each chimp was paired with a partner who was given a choice of four ropes to pull, each with a different outcome: give just herself a banana pellet; give just the subject a pellet; give both of them pellets; or forgo her turn and let her partner make the decision instead.

Unbeknownst to these partner chimpanzees, the chimp that always started the game—a female named Tai—was trained to always choose the last option, giving up her turn. From the partner’s point of view, this was a risky choice, Grüneisen says, as Tai risked losing out entirely on the banana pellets. Over dozens of trials, after Tai gave up her turn, the six partners pulled the rope that rewarded both themselves and Tai with a treat 75% of the time, indicating they valued her risking her own treats to help them.

But the researchers also wanted to see whether the subjects were willing to give up some of their own reward to repay Tai for her perceived kindness. “That kind of reciprocity is often claimed to be a landmark of human cooperation, and we wanted to see how far we could push it with the chimps,” Grüneisen says.

The team repeated the experiment, except this time when Tai passed the turn to the subjects, the subjects had the option of either giving themselves four banana pellets and Tai none, or giving both themselves and Tai only three banana pellets. The subjects chose the sacrifice option 44% of the time, compared with 17% of the time when the experimenters, not Tai, made the initial decision. This suggests that the chimps frequently felt compelled to reward Tai for her perceived unselfishness, even at their own expense, the researchers report today in the Proceedings of the National Academy of Sciences (PNAS).

“We were very surprised to get that finding,” Grüneisen says. “This psychological dimension to chimps’ decision-making, taking into account how much a partner risked to help them, is novel.”

The second study, also published today in PNAS, looked at what motivates male chimps to risk life and limb on patrol missions. Male chimps in the wild often team up and silently stalk the group’s boundaries single-file, sniffing for intruders. These can be costly excursions: About a third of the time, they meet chimps from a rival group, and occasionally the encounters turn bloody. So patrolling chimps risk injury or even death.

According to classic behavioral theories, chimps should put themselves in such peril only if they have offspring or close maternal relatives in the group. Yet, after analyzing behavior and relationship data from 3750 male chimps in Ngogo, Uganda, collected over the past 20 years, researchers learned that although that was true for most chimps, more than a quarter of the patrollers had no close relations in the group. What’s more, males who didn’t join these all-male patrols didn’t appear to face any repercussions, says the study’s lead author, anthropologist Kevin Langergraber from Arizona State University in Tempe. So, it was a bit surprising that so many chimps risked it.

He and his colleagues suggest that a theory known as group augmentation best explains these findings. This theory posits that by patrolling to protect the group’s food supply and expand its territory, the entire group becomes more attractive to females and improves each individual male’s chances of reproducing.

Anne Pusey, another evolutionary anthropologist at Duke who is unaffiliated with the studies, agrees it’s a reasonable hypothesis. Protecting and expanding the group’s territory, she says, would “secure or increase the space and food supply for resident females, as well as future immigrant females, with whom [the males] will eventually mate and have a chance of siring offspring.” More and healthier females means each individual male has a greater chance at producing offspring.

Langergraber adds that such behavior might serve as an evolutionary basis for human cooperation within huge, diverse communities. “One of the most unusual things about human cooperation is its large scale,” he says. “Hundreds or thousands of unrelated individuals can work together to build a canal, or send a human to the moon. Perhaps the mechanisms that allow collective action among chimpanzees served as building blocks for the subsequent evolution of even more sophisticated cooperation later in human evolution.”

Dr Peter Walsh, from the University of Cambridge, who led the research, told BBC News: "Now that we have shown this is a safe vaccine, it's really a moral imperative that we use it.

"The disease is a huge threat to gorillas right now. We vaccinate our children, we vaccinate livestock, we vaccinate our pets, we vaccinate wildlife - why aren't we vaccinating our closest relatives?"

Gorilla losses

The outbreak of Ebola in West Africa that started in 2013 highlighted the devastating toll that the disease can have in humans: more than 11,000 people are estimated to have died.

But now there is a vaccine that has been shown to be 100% effective against the disease, and the hope is that it will prevent anything on this scale from happening again.

Some scientists say gorillas could benefit from immunization, too.

There are whole areas, hundreds of kilometres in every direction, that have just been wiped out of gorillasDr Peter Walsh, University of Cambridge

And Ebola in humans and great apes is closely linked. Many human outbreaks have started after people came into contact with infected gorilla or chimp carcasses or bushmeat (the 2014 outbreak is not thought to have started this way but instead through contact with Ebola-carrying bats).

The disease is extremely deadly for our primate cousins: if chimps or gorillas are infected, there is a 90-98% chance that they will die.

Many thousands of gorillas, which are also facing threats from poaching and habitat loss, are thought to have died from the disease.

"There are whole areas, hundreds of kilometres in every direction, that have just been wiped out of gorillas," said Dr Walsh.

Image copyrightMATTHIAS SCHNELLImage captionThe trial was carried out before a ban on chimp research came into place in the US

To see if immunization could help, a vaccine was tested on 10 captive chimpanzees at a research centre at the University of Louisiana Lafayette in the US.

Because chimps and gorillas are so closely related, the researchers assumed that if the vaccine worked in chimps it would work for gorillas also.

Six animals were given the drug by mouth and four were injected with it.

"We found the vaccine gave a very robust immune response and didn't cause any health complications," said Dr Walsh.

Dr Walsh acknowledged the trial was small, but said it was stopped early when a ban on the use of chimpanzees in biomedical research came into force in the US in 2015.

He added that most other parts of the world either have moratoriums or bans on great ape research, and said that sanctuaries and zoos were either unwilling or unequipped to carry out trials.

"Effectively, we just have to start doing it in the wild now," he explained.

He wants to see if lacing sweet treats with the vaccine or using remotely operated sprays or darts could help to immunize wild animals.

He is also looking at how to ensure the vaccine remains effective and stable in the heat of the forest and wants to further examine the dosage.

Image copyrightSCIENCE PHOTO LIBRARYImage captionSome conservationists think more research is needed before a vaccine is used in the wild

Liz Macfie, vice chair of the International Union for Conservation of Nature's section on great apes, said that the results of the trial were encouraging and promising.

But she told the BBC that rolling out a wider vaccination programme would be difficult.

She said: "Some wild apes are habituated to tourists or researchers' presence, so some you can approach. But the majority of the populations are completely unhabituated and it would be very difficult to provide a vaccine into a group of unhabituated apes."

She also said there were some concerns about safety.

There are other vaccine approaches under consideration but they will all require more researchSarah Olson , Wildlife Conservation Society

"There's always the risk when you use a vaccine on wild animals that there is an associated pathology or infections that might spread… It's a small sample size that [this vaccine] has been tested in and we don't really know about all of the other effects."

But she added that conservationists now needed to come together to look at studies like this and assess the best way forward.

These thoughts were echoed by Sarah Olson, associate director of wildlife epidemiology for the Wildlife Conservation Society.

"An oral vaccine formulation would need to be stable and edible, as gorillas are really picky eaters, safe for target and non-target species impacts, and effective and affordable," she said.

"There are other vaccine approaches under consideration but they will all require more research."

However, Dr Walsh told the BBC that the situation was urgent.

"The Ebola situation is quiet right now in Africa, and there is a danger that people are going to think: 'Oh, that's not a problem anymore, we don't have to worry about it'.

"But believe me, it's been quiet before and then it's come roaring back.

"And that's why, instead of waiting for the crisis, we need to start to develop the tools to protect these animals in the future."

Majority of primate species may vanish in next 25 to 50 years

Andy Cohan | New Scientist | 18/01/2017

All apes are under threat - Conservation International/photo by Russell A. Mittermeier

The majority of the world’s primates are in deep trouble. There are as few as 20 or 30 Hainan gibbons left in China, and the trapdoor of extinction is gaping for the Javan slow loris. Even numbers of Madagascar’s iconic ring-tailed lemur have slumped to around 2000.

These could be the next primates to disappear from our planet. But overall, the picture is even bleaker, with 60 per cent of all primate species globally predicted to vanish within between 25 and 50 years.

That’s the gloomy conclusion from the largest ever review of the survival prospects of the world’s 504 known species of non-human primate, 85 of them discovered since 2000. “This paper is a synthesis of the factors, at all scales, that are causing declines and extinctions,” says Anthony Rylands of Conservation International, joint lead author of the report.

The biggest harbinger of doom is clearance of forests for agriculture, both by local farmers and by big agro-industrial producers of commodities such as palm oil and rubber. Between 1990 and 2010, for example, agricultural expansion into primate habitats was estimated at 1.5 million square kilometres, an area three times that of France.

Save our species

“Our paper is a plea to address the consequences of destruction and degradation of primate habitats worldwide,” says Rylands. “Agriculture as a threat can only be dealt with at all scales, influenced as it is by global trends, by government policies, corporate practices and malpractices, and regional and local policies.”

Much effort could focus on just four countries – Brazil, Indonesia, Madagascar and the Democratic Republic of the Congo – which host two-thirds of all primate species. Madagascar could be a good place to start as all 111 of its lemurs are unique to the island, and 94 per cent are threatened.

“Madagascar is far and away the highest primate conservation priority, in a land area that’s less than 1 per cent of all known primate habitat, but which in Madagascar is already 90 per cent cleared,” says co-author Russell Mittermeier, also at Conservation International. “The most endangered there is the northern sportive lemur, down to just 50 individuals.”

All 39 ape species and subspecies, including orangutans, are now ranked as threatened with extinction. All 19 colobus species in Africa are threatened, with 12 critically endangered or endangered. And all Asian lorises are in trouble, not just from habitat loss but also through poaching and trade in their body parts.

Primates face impending extinction - what's next?

This is a commentary by Russell A. Mittermeier, Executive Vice-Chair of Conservation International and Chair of the IUCN/SSC Primate Specialist Group, and Anthony B. Rylands, Senior Research Scientist of Conservation International and Deputy-Chair of the IUCN/SSC Primate Specialist Group. Mittermeier and Rylands are co-authors of a paper published last week in Science Advances. The views expressed are their own.

Nonhuman primates are on the decline almost everywhere.

The third most diverse Order of mammals, primates are under the highest level of threat of any larger group of mammals, and among the highest of any group of vertebrates

63% of primates are threatened, meaning that they fall into one of the three IUCN categories of threat—Critically Endangered, Endangered, and Vulnerable.

This post is a commentary - the views expressed are those of the authors.

The Year of the Monkey has just ended, and won’t come around again for another 12 years. In the meantime, what is happening with our closest living relatives, the nonhuman primates? A recent paper in Science Advances by 31 of us indicates that we are facing an impending extinction episode if we don’t ramp up our actions in a major way over the remainder of this decade and before the next Year of the Monkey comes around again.

Our paper, led by Alejandro Estrada of the National Autonomous University of Mexico and Paul Garber from the University of Illinois, Urbana, and including the two of us as coauthors, highlights the fact that nonhuman primates are on the decline almost everywhere. The third most diverse Order of mammals (after the rodents and bats), they are under the highest level of threat of any larger group of mammals, and among the highest of any group of vertebrates. Indeed, our latest assessments, carried out under the auspices of the International Union for Conservation of Nature’s Species Survival Commission (IUCN/SSC) Primate Specialist Group (PSG) and following the long-established Red-listing process of IUCN indicate that at least 63% are threatened, meaning that they fall into one of the three IUCN categories of threat—Critically Endangered, Endangered, and Vulnerable. Of these, 298 (or 43% of all primates) are Critically Endangered and Endangered, meaning, quite simply, that they are in big trouble. This information is based on four Red-Listing workshops carried out for the four major regions in which nonhuman primates occur, the Neotropics (South and Central America and Mexico – January, 2015), Asia (November, 2015), Africa (April, 2016), and Madagascar (July, 2012, soon to be updated in a second workshop). The results from these workshops aren’t even fully analyzed yet, and indications are that the threat percentages could climb still further. Stay tuned.

Abstract

Nonhuman primates, our closest biological relatives, play important roles in the livelihoods, cultures, and religions of many societies and offer unique insights into human evolution, biology, behavior, and the threat of emerging diseases. They are an essential component of tropical biodiversity, contributing to forest regeneration and ecosystem health. Current information shows the existence of 504 species in 79 genera distributed in the Neotropics, mainland Africa, Madagascar, and Asia. Alarmingly, ~60% of primate species are now threatened with extinction and ~75% have declining populations. This situation is the result of escalating anthropogenic pressures on primates and their habitats—mainly global and local market demands, leading to extensive habitat loss through the expansion of industrial agriculture, large-scale cattle ranching, logging, oil and gas drilling, mining, dam building, and the construction of new road networks in primate range regions. Other important drivers are increased bushmeat hunting and the illegal trade of primates as pets and primate body parts, along with emerging threats, such as climate change and anthroponotic diseases. Often, these pressures act in synergy, exacerbating primate population declines. Given that primate range regions overlap extensively with a large, and rapidly growing, human population characterized by high levels of poverty, global attention is needed immediately to reverse the looming risk of primate extinctions and to attend to local human needs in sustainable ways. Raising global scientific and public awareness of the plight of the world’s primates and the costs of their loss to ecosystem health and human society is imperative.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

She was not observed eating any plants, so she remained completely dependent on her mother's milk long after a baby chimp would usually have been weaned.

She had a growth on her stomach (Credit: Michio Nakamura)

"We suspect that her feeding limitations were due to her lack of motor ability and that she might have suffered from a lack of nutrition because of her milk diet, at least in her latter life," the authors report.

As well as her limited physical abilities, XT11 had an abdominal hernia on her stomach (see above), spinal damage and an extra, inactive finger on her left hand.

Her eyes looked empty, her mouth was often half open, and she was unable to sit without support.

She was able to hold onto her mother's hair, but her feet did not have enough strength to grip, so she mostly dangled.

The infant's older sister also frequently cared for her (Credit: Michio Nakamura)

Caring for a disabled infant forced Christina to change her behaviour. She stopped fishing for ants in trees, because she needed her hands free to carry XT11.

"The mother of a severely disabled infant probably experiences more stress than other mothers because she must provide intensive care for longer," the authors write.

"There were some cases where the mother spontaneously gave the infant to the elder daughter. This is quite unusual for a mother to do," says Michio Nakamura, co-author of the study from Kyoto University, Japan.

"While the elder sister was taking care of the disabled infant, the mother climbed on a tree to feed on fruits," he told BBC Earth.

But when her sister had her own child, this extra care stopped.

XT11's relatives were not allowed to groom or carry her, which is unusual. The mother may have understood that it would not be safe for others to carry her child, as they did not fully understand her needs.

The cause of her death is unclear. It may have been due to complications brought on by her limited diet.

The disabled infant often had empty eyes and half-open mouth (Credit: Takuya Matsumoto)

Although it is not uncommon for primates to be born with disabilities, only two chimpanzee infants with disabilities have been observed previously.

Both were captive. They were neglected or rejected by their mothers, so humans helped to care for them. One died at 17 months: the other reached 24 months but only after receiving several blood transfusions.

That such care has now been witnessed in the wild, in our closest living relatives, hints that this behaviour has a long evolutionary history. Our common ancestor with chimpanzees may have displayed similar levels of care.

"Our observation that the elder sister took care of the disabled infant might shed light on how non-maternal care to disabled individuals evolved," says Nakamura.

An analysis by de Manuel Montero et al. suggests that bonobos mated with chimpanzees between 550,000 and 200,000 years ago, resulting in genetic admixture between the two species. Credit: Carla Schaffer / Science

For the first time, scientists have revealed ancient gene mixing between chimpanzees and bonobos, mankind's closest relatives, showing parallels with Neanderthal mixing in human ancestry. Published today in the journal Science, the study from scientists at the Wellcome Trust Sanger Institute and their international collaborators showed that 1% of chimpanzee genomes are derived from bonobos.

The study also showed that genomics could help reveal the country of origin of individual chimpanzees, which has strong implications for chimpanzee conservation.

Chimpanzees and bonobos are great apes found only in tropical Africa. They are endangered species and are supposedly fully protected by law, yet many chimpanzees and bonobos are captured and held illegally.

To aid the conservation effort, researchers analysed the whole genome sequences of 75 chimpanzees and bonobos, from 10 African countries, and crucially included 40 new wild-born chimpanzees from known geographic locations. They discovered that there was a strong link between the genetic sequence of a chimpanzee, and their geographic origin.

Dr Chris Tyler Smith, from the Wellcome Trust Sanger Institute, said: "This is the largest analysis of chimpanzee genomes to date and shows that genetics can be used to locate quite precisely where in the wild a chimpanzee comes from. This can aid the release of illegally captured chimpanzees back into the right place in the wild and provide key evidence for action against the captors."

Chimpanzees and bonobos are the closest living relatives of human beings. They diverged from a common ancestor between 1.5 and 2 million years ago and live in different areas of tropical Africa. Until now, it was thought that gene flow between the species would have been impossible, as they were physically separated by the Congo River.

The study confirmed a main separation between chimpanzees and bonobos approximately 1.5 million years ago, and the presence of four chimpanzee subspecies in different regions. However, the researchers also found there were two additional gene flow events between the chimpanzee and bonobo populations, indicating that at least some individuals found their way across the river.

Dr Yali Xue, from the Sanger Institute, said: "We found that central and eastern chimpanzees share significantly more genetic material with bonobos than the other chimpanzee subspecies. These chimpanzees have at least 1% of their genomes derived from bonobos. This shows that there wasn't a clean separation, but that the initial divergence was followed by occasional episodes of mixing between the species.

The study also included researchers from Spain, Copenhagen Zoo and the University of Cambridge and showed that there have been at least two phases of secondary contact, 200-550 thousand years ago and around 150 thousand years ago, mirroring what is believed to have happened during the last 100 thousand years of the evolution of humans.

Dr Tomàs Marquès-Bonet, leader of the study from the Institute of Biological Evolution (University Pompeu Fabra and CSIC), Barcelona, said: "This is the first study to reveal that ancient gene flow events happened amongst the living species closest to humans - the bonobos and chimpanzees. It implies that successful breeding between close species might have been actually widespread in the ancestors of humans and living apes."

Chimpanzees stress less when a pal is around

The ape's stress hormones drop when loved ones are nearby, suggesting healthy emotional bonds also lead to a healthier body.

Having a good buddy around decreases stress hormones in chimpanzees – even in potential life-or-death situations.

FUSE / GETTY IMAGES

Seeking out close mates during stressful times isn’t just a habit of us humans – chimpanzees, too, need a little help from their friends when they’re strung out.

Research published in Nature Communications suggests the apes in dangerous situations can keep stress hormone levels if friends are close by. If you’re a chimp, a spot of grooming from a loved one can also significantly reduce stress – and there are knock-on effects too.

“For animals, including humans, there is much evidence that individuals who maintain stable, close social bonds have greater reproductive success, increased longevity and better health compared with those who do not,” the research states.

Roman Wittig at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues measured the stress levels of 17 wild chimps in various situations, first with their friends in proximity, and then in the company of strangers – or rather, chimps without close social bonds.

For the record, a “close social bond” between chimps was observed by mutual grooming, support and food-sharing between two individuals, maintained over several months – or even years.

The team examined chimps in three scenarios: at rest, engaged in an everyday activity (such as grooming) and in a high-stress situation.

The latter was either naturally observed as chimpanzee bands crossed paths in the wild or created by playing the tree-drumming sounds of another group to simulate a rival encounter – a potentially life-threatening scenario for a chimp.

In each of these experiments, the team observed levels of glucocorticoids – a class of stress-related hormones – by testing each chimpanzee’s urine.

Their findings show that across all three scenarios, including the potentially lethal encounters, stress hormone levels weren’t elevated when bond partners were close by.

Interestingly, glucocorticoid levels were at their lowest during grooming, but only if the activity involved a close friend.

The researchers say this result echoes previous studies on humans, too, and has implications for health and survival.

The researchers say stress is a major cause of poor health and mortality in humans and other social mammals, partly because it can disrupt the activity of the hypothalamic-pituitary-adrenocortical axis – a complex set of interactions among the hypothalamus and pituitary gland, which are both in the brain, and the adrenal glands atop the kidneys.

The axis has major effects on vital functions such as the metabolic and cardiovascular systems.

The researchers say their results suggest “that regular and repeated, everyday affiliations have the potential to regularly and repeatedly re-align the [hypothalamic-pituitary-adrenocortical] axis throughout the day”.

Chimpanzees stress less when a pal is around

The ape's stress hormones drop when loved ones are nearby, suggesting healthy emotional bonds also lead to a healthier body.

Having a good buddy around decreases stress hormones in chimpanzees – even in potential life-or-death situations.

FUSE / GETTY IMAGES

Seeking out close mates during stressful times isn’t just a habit of us humans – chimpanzees, too, need a little help from their friends when they’re strung out.

Research published in Nature Communications suggests the apes in dangerous situations can keep stress hormone levels if friends are close by. If you’re a chimp, a spot of grooming from a loved one can also significantly reduce stress – and there are knock-on effects too.

“For animals, including humans, there is much evidence that individuals who maintain stable, close social bonds have greater reproductive success, increased longevity and better health compared with those who do not,” the research states.

Roman Wittig at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues measured the stress levels of 17 wild chimps in various situations, first with their friends in proximity, and then in the company of strangers – or rather, chimps without close social bonds.

For the record, a “close social bond” between chimps was observed by mutual grooming, support and food-sharing between two individuals, maintained over several months – or even years.

The team examined chimps in three scenarios: at rest, engaged in an everyday activity (such as grooming) and in a high-stress situation.

The latter was either naturally observed as chimpanzee bands crossed paths in the wild or created by playing the tree-drumming sounds of another group to simulate a rival encounter – a potentially life-threatening scenario for a chimp.

In each of these experiments, the team observed levels of glucocorticoids – a class of stress-related hormones – by testing each chimpanzee’s urine.

Their findings show that across all three scenarios, including the potentially lethal encounters, stress hormone levels weren’t elevated when bond partners were close by.

Interestingly, glucocorticoid levels were at their lowest during grooming, but only if the activity involved a close friend.

The researchers say this result echoes previous studies on humans, too, and has implications for health and survival.

The researchers say stress is a major cause of poor health and mortality in humans and other social mammals, partly because it can disrupt the activity of the hypothalamic-pituitary-adrenocortical axis – a complex set of interactions among the hypothalamus and pituitary gland, which are both in the brain, and the adrenal glands atop the kidneys.

The axis has major effects on vital functions such as the metabolic and cardiovascular systems.

The researchers say their results suggest “that regular and repeated, everyday affiliations have the potential to regularly and repeatedly re-align the [hypothalamic-pituitary-adrenocortical] axis throughout the day”.